Prevalence of antigliadin IgA antibodies in psoriasis vulgaris and response of seropositive patients to a gluten-free diet

INTRODUCTION: The course of psoriasis relies on a variety of metabolic and immunological parameters. Identification of underlying pro-inflammatory conditions and their control is desired for optimal management. BACKGROUND: Increased prevalence of serum markers for celiac disease has been reported among patients with psoriasis. The likelihood of occult celiac disease in a subpopulation of patients has been postulated and gluten-free diets have been reported to be effective. PATIENTS AND METHODS: The prevalence of gliadin IgA antibodies was assessed among patients with psoriasis in an urban population. The clinical effects of a strict gluten-free diet were followed. RESULTS: Over a 2-year period, 97 patients with Psoriasis Area and Severity Index greater than 2.4 were recruited from a population followed in a dermatology clinic. Gliadin IgA antibodies were assessed in all participants and in 91 controls. Elevated gliadin IgA antibodies were found in 13 patients (14%) and two controls (2%). Values in five patients were assessed as greater than 30.0 U/mL or “strong positive” according to the manufacturer of the assay. All 13 patients were placed on a strict gluten-free diet without any other modifications in their ongoing treatment of psoriasis. Improvement of psoriatic lesions was observed in all patients with positive gliadin IgA antibodies but the decline in the Psoriasis Area and Severity Index score and the scaling down of pharmaceutical treatment was more pronounced in the five patients with strong positive gliadin IgA indicating an immune aberration amenable to diet changes. CONCLUSION: Prevalence of antigliadin IgA antibody is significant among patients with psoriasis not diagnosed with celiac disease or non-celiac gluten sensitivity. For all its limitations, antigliadin IgA testing can identify patients likely to benefit from gluten-free diets.